Synthesis of butyl acrylate-styrene block copolymers in emulsion by reversible addition-fragmentation chain transfer: Effect of surfactant migration upon film formation

Abstract

The synthesis of block copolymers in an environmentally friendly medium was carried out in emulsion polymerizations through the reversible addition‐fragmentation chain transfer process, using a transfer active xanthate (MADIX) agent, under batch and starved‐feed conditions. First, ab initio experiments were carried out to prepare a seed of PBA dormant chains (i.e., poly(butyl acrylate) (PBA) polymer attached with a transfer active xanthate). The M̄n and polydispersity were predicted accurately with numerical simulations and equations derived by Müller from the method of moments. Those seeds were then used in a second‐stage polymerization under starved‐feed and batch conditions to prepare composite polymer colloids of block PBA‐co‐poly(styrene). Under starved feed conditions, approximately 90% of total polymer consisted of blocks, whereas under batch conditions only 70% consisted of blocks, which is proposed to be due a higher entry efficiency and thus greater termination rate. The films of these latexes were examined by atomic force microscopy. Surfactant migration to the surface increased with an increase in the amount of MADIX, resulting from a combination of a smaller particle size and a lower average molecular weight. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4206–4217, 2000

Living Radical Polymerization by the RAFT Process

“…[9] Much research has shown that the success in RAFT emulsion polymerization depends strongly on the choice of RAFT agent and polymerization conditions. [9,[175][176][177][178][179][180][181][182][183] Most work has focussed on styrene polymerization, [9,176,177,183] although RAFT emulsion polymerizations of BA [178] and methcrylates [9,13] have also been reported. Use of cumyl dithiobenzoate 22 as RAFT agent in ab initio emulsion polymerization of styrene is not recommended.…”

Macromolecular Design via the Interchange of Xanthates (MADIX): Polymerization of Styrene with O‐Ethyl Xanthates as Controlling Agents

“…Since then, significant effort has been devoted to these new versatile approaches towards controlled polymer synthesis, including the development of dithiocarbamate controlling agents, [9,10] novel controlled homopolymers like poly-(acrylic acid) [11] and block copolymers, [12] and the first successful applications in dispersed media. [13,14] O-Ethyl xanthates of the general structure R-S(C S)-OEt (X 1-8 ) with varying substituents R have been synthesized and used for the thermal bulk radical polymerization of styrene. The present study deals with the influence of the nature of the leaving group R on the level of control of the polymerization of styrene (St).…”

A detailed mechanistic study of bulk MADIX of styrene and its chain extension

“…This temperature has been selected in view of a future extension to MADIX emulsion polymerization. 33,74,75 Moreover, the self-initiation of styrene is suppressed, simplifying the overall kinetic description. 76 Temperature control was possible through in situ measurements via a thermocouple inserted in the rubber septum.…”